The most popular story of how the Thistle became Scotland's
symbol involves the events surrounding the Battle of Largs in 1263.

For more than 600 years most of Scotland had been part of the Kingdom
of Norway. By 1263 Norway seemed to no longer have any interest in
Scotland and King Alexander III proposed to buy back the Western
Isles and Kintyre, still Norwegian territory.

This re-awoke Norse interest in Scotland and King Haakon IV attacked
with a large force to re-establish his authority. The Norsemen tried to
surprise the Scots by landing on the Coast of Largs at night. The attackers
removed their footwear for a silent approach but found themselves on ground
covered with thistle. It is said that one of the men stepped on thistle
spines and thorns and cried out. His shouts warned the Scots, who then
defeated the Norsemen, thus saving Scotland.

The first use of the Scottish Thistle as a royal symbol was on silver
coins issued by James III in 1470.